Using z-scores to evaluate accounting students: a test of Weinstein’s suggestion

Based on analysis using hypothetical data, Weinstein suggested that z-scores should be used in the determination of accounting students’ grades. The computation of z-scores mitigates the subjectivity caused by differences in the variances of the individual components that make up the total points for the course. We tested Weinstein’s suggestion using actual data to determine the degree to which subjectivity resulting from different variances influenced grades based on a total point distribution. The effect on actual final letter grades assigned was determined by comparing the rankings in grade distributions based on total points versus rankings based on z-scores. Findings show minimal overall effects on letter grade differences between total point and z-score-based methods. Because the results using actual data in our study found smaller differences than suggested by Weinstein’s hypothetical data, our findings do not indicate a compelling need to use a z-score standardization method in determining students’ grades. However, since using z-scores is easy and final grade rankings differed in some cases, instructors might find it useful to compute z-scores in addition to their normal grading procedures.     

The Exploitation of Inside Information at the Wall Street Journal: A Test of Strong Form Efficiency

The study examines if tradings on stocks based on the inside information about the “Heard on the Street” column of the Wall Street Journal could generate abnormal returns. We found significant abnormal returns on days t =?1 and t= 0 (publication date) for the stocks related to insider trading. For a comparable control group of noninsider traded stocks, the abnormal returns were not significant on day t=?1 but were significant on day t= 0. The abnormal returns for the insider trade group on days t=?1 and t= 0 were greater than the returns for the control group. The results indicate that the inside information was the cause for the differences.     

Consistency and asymptotic normality of maximum likelyhood estimators

Abstract

Let the random variable X denote the time taken in completion of a process. For a fixed a, if the observed value of X is less than a, the X is observable, but if X is greater than a, the process is tampered with and is accelerated or decelerated at time a by some unknown factor α, and Y=a+α(X-a) is observed. If the experimenter has only partial control over the experiment, it may be difficult to get several observations on Y corresponding to the same a value. Thus we have a set of independent but not identically distributed observations. The large sample behavior of m.l.e. of the unknown parameters based on tampered random variables Y ^b1 , ..., Y ^bn is studied. If X follows an exponential distribution with mean (1/--), ... the consistency and asymptotic normality of the m.l.e. of α and -- is established under mild conditions on a ^b1, a ^b2, ... The conditions needed for establishing the consistency of m.l.e. of lX are given when X follows a uniform distribution U(O, --) or when X has any known distributional form     

Fund Manager Use of Public Information: New Evidence on Managerial Skills

We show theoretically that the responsiveness of a fund manager's portfolio allocations to changes in public information decreases in the manager's skill. We go on to estimate this sensitivity (RPI) as the R² of the regression of changes in a manager's portfolio holdings on changes in public information using a panel of U.S. equity funds. Consistent with RPI containing information related to managerial skills, we find a strong inverse relationship between RPI and various existing measures of performance, and between RPI and fund flows. We also document that both fund‐ and manager‐specific attributes affect RPI.     

Measuring systemic risk in the European banking sector: a copula CoVaR approach

We propose a new methodology based on copula functions to estimate CoVaR, the Value-at-Risk (VaR) of the financial system conditional on an institution being under financial distress. Our Copula CoVaR approach provides simple, closed-form expressions for various definitions of CoVaR for a broad range of copula families and allows the CoVaR of an institution to have time-varying exposure to its VaR. We extend this approach to estimate other ‘co-risk’ measures such as Conditional Expected Shortfall (CoES). We focus on a portfolio of large European banks and examine the existence of common market factors triggering systemic risk episodes. Further, we analyse the extent to which bank-specific characteristics such as size, leverage, and equity beta are associated with institutions' contribution to systemic risk and highlight the importance of liquidity risk at the outset of the financial crisis in summer 2007. Finally, we investigate the link between macroeconomy and systemic risk and find that changes in major macroeconomic variables can contribute significantly to systemic risk.     

Swap variance hedging and efficiency: The role of high moments

In this article, we propose a new theoretical approach for developing hedging strategies based on swap variance (SwV). SwV is a generalized risk measure equivalent to a polynomial combination of all moments of a return distribution. Using the S&P 500 index and West Texas Intermediate (WTI) crude oil spot and futures price data, as well as simulations by varying the distribution of asset returns, we investigate the dynamic differences between hedge ratios and portfolio performances based on SwV (with high moments) and variance (without high moments). We find that, on average, the minimizing-SwV hedging suggests more short futures contracts than minimizing-variance hedging; however, when market conditions deteriorate, the minimizing-SwV hedging suggests fewer short positions in futures. The superior posthedge performances of the mean-SwV hedged portfolios over the mean-variance hedged portfolios in highly volatile or extremely calm markets confirm the efficiency of the mean-SwV hedging strategy.     

The Distributional Efficiency of Alternative Regulatory Regimes: A Real Option Approach

This paper studies the effects of regulatory constraints on firm's irreversible investment decisions. The RPI–x rule is compared to a profit sharing rule, which increases the x factor in case profits go beyond a given level.When the firm has an option to delay investment, these rules have the same impact on investment choices. As profit sharing has a greater ability to extract rents, however, it is more efficient than the RPI–x rule.     

Reflections on the scholarship of teaching: A report on the Colloquium on Change in accounting education, 2005

The ninth annual meeting in a series entitled Colloquium on Change in Accounting Education recently concluded. My attendance at this meeting prompted a broader reflection on the scholarship of teaching and the purpose of academic conferences.     

“Relative Importance of Risk Sources in Insurance Systems”, Edward W. Frees,April 1998

Abstract

This paper considers a Sparre Andersen collective risk model in which the distribution of the interclaim time is that of a sum of n independent exponential random variables; thus, the Erlang(n) model is a special case. The analysis is focused on the function φ(u), the expected discounted penalty at ruin, with u being the initial surplus. The penalty may depend on the deficit at ruin and possibly also on the surplus immediately before ruin. It is shown that the function φ(u) satisfies a certain integro-differential equation and that this equation can be solved in terms of Laplace transforms, extending a result found in Lin (2003). As a consequence, a closed-form expression is obtained for the discounted joint probability density of the deficit at ruin and the surplus just before ruin, if the initial surplus is zero. For this formula and other results, the roots of Lundberg’s fundamental equation in the right half of the complex plane play a central role. Also, it is shown that φ(u) satisfies Li’s (2003) renewal equation. Under the assumption that the penalty depends only on the deficit at ruin and that the individual claim amount density is a combination of exponential densities, a closed-form expression for φ(u) is derived. In this context, known results of the Cauchy matrix are useful. Surprisingly, certain results are best expressed in terms of divided differences, a topic deleted from the actuarial examinations at the end of last century.     

Hedging with Two Futures Contracts: Simplicity Pays

We propose to use two futures contracts in hedging an agricultural commodity commitment to solve either the standard delta hedge or the roll‐over issue. Most current literature on dual‐hedge strategies is based on a structured model to reduce roll‐over risk and is somehow difficult to apply for agricultural futures contracts. Instead, we propose to apply a regression based model and a naive rules of thumb for dual‐hedges which are applicable for agricultural commodities. The naive dual strategy stems from the fact that in a large sample of agricultural commodities, De Ville, Dhaene and Sercu (2008) find that GARCH‐based hedges do not perform as well as OLS‐based ones and that we can avoid estimation error with such a simple rule. Our semi‐naive hedge ratios are driven from two conditions: omitting exposure to spot price and minimising the variance of the unexpected basis effects on the portfolio values. We find that, generally, (i) rebalancing helps; (ii) the two‐contract hedging rules do better than the one‐contract counterparts, even for standard delta hedges without rolling‐over; (iii) simplicity pays: the naive rules are the best one–for corn and wheat within the two‐contract group, the semi‐naive rule systematically beats the others and GARCH performs worse than OLS for either one‐contract or two‐contract hedges and for soybeans the traditional naive rule performs nearly as well as OLS. These conclusions are based on the tests on unconditional variance ( Diebold and Mariano, 1995 ) and those on conditional risk ( Giacomini and White, 2006 ).     

Market impact: a systematic study of the high frequency options market

This paper deals with a fundamental subject that has seldom been addressed in recent years, that of market impact in the options market. Our analysis is based on a proprietary database of metaorders—large orders that are split into smaller pieces before being sent to the market—on one of the main Asian markets. In line with our previous work on the equity market [Said, E., Bel Hadj Ayed, A., Husson, A. and Abergel, F., Market impact: A systematic study of limit orders. Mark. Microstruct. Liq., 2018, 3(3&4), 1850008.], we propose an algorithmic approach to identify metaorders, based on some implied volatility parameters, the at the money forward volatility and at the money forward skew. In both cases, we obtain results similar to the now well-understood equity market: Square-Root Law, Fair Pricing Condition and Market Impact Dynamics.     

The representation of nano as a risk in Swedish news media coverage

Focusing on the role of language in categorization and on the broad conceptual field centred on the morpheme nano, this study addresses the association between phenomena referred to by words having nano as a constituent and risk in Swedish newspaper reporting. The study raises the question of how nano-associated phenomena (e.g. nanotechnology and nanoparticle) are represented as risks? Articles considered for analysis contain both a word having nano as a constituent and the Swedish words for risk or danger. Articles representing nano-associated phenomena (e.g. nanotechnology and nanoparticle) as risks mainly fall into one of five groups: (I) nanotechnology, without reference to particles, materials or products; (II) nanotechnology, nanoparticles, nanomaterials and/or products containing such particles and materials; (III) nanoparticles in products, but without reference to nanotechnology; (IV) nanotechnology and nanorobots; and (V) non-nanotechnological nanoparticles. For each group, using a theoretical approach addressing the relational nature of risk, the paper analyses representations of objects at risk, bad outcomes, causal conditions, reference to applications and sources cited. Various patterns of these categories emerge for the five groups, indicating a diversified set of associations between nano and risk. In certain respects, the findings support the results of other studies of media reporting on nanotechnology, suggesting certain international patterns of newspaper coverage of nanotechnology drawing on both science and science fiction.     

India’s strategic future: 2025

Based on the geopolitical developments in India’s neighbouring countries and India’s response to them, this paper depicts four scenarios—Storms and Fires, Rainbow in the Sky, Light and Shadows and Across Space. Each scenario explores a set of possible events and the consequences triggered by it. While Storms and Fires is based on the rise of a sharp nationalist Indian sentiment in the face of heightened security tensions in the region, Across Space outlines the future of India’s worldview shaped by the present government’s policy of US primacy. Light and Shadows is based on differential policy towards neighbours—conflict with Pakistan and cooperation with other neighbours. This scenario is predicated on the supremacy of economic objectives whereas Rainbow in the Sky is based on the regional cooperation as the primary guiding force of the Indian foreign policy. Though major geopolitical events in its neighbourhood will impact the immediate future of India, India’s response and internal strengths and weaknesses will determine its long-term future. It is therefore essential for the country to develop a well considered trajectory of its strategic options for the next 25 years.     

On a multivariate Markov chain model for credit risk measurement

In this paper, we use credibility theory to estimate credit transition matrices in a multivariate Markov chain model for credit rating. A transition matrix is estimated by a linear combination of the prior estimate of the transition matrix and the empirical transition matrix. These estimates can be easily computed by solving a set of linear programming (LP) problems. The estimation procedure can be implemented easily on Excel spreadsheets without requiring much computational effort and time. The number of parameters is O(s² m² ), where s is the dimension of the categorical time series for credit ratings and m is the number of possible credit ratings for a security. Numerical evaluations of credit risk measures based on our model are presented.     

American and European options in multi-factor jump-diffusion models,near expiry

We derive a general formula for the time decay θ for out-of-the-money European options on stocks and bonds at expiry, in terms of the density of jumps F(x,dy) and the payoff g ₊: −θ(x)=∫ g(x+y)₊ F(x,dy). Explicit formulas are derived for the standard put and call options, exchange options in stochastic volatility and local volatility models, and options on bonds in ATSMs. Using these formulas, we show that in the presence of jumps, the limit of the no-exercise region for the American option with the payoff (−g)₊ as time to expiry τ tends to 0 may be larger than in the pure Gaussian case. In particular, for many families of non-Gaussian processes used in empirical studies of financial markets, the early exercise boundary for the American put without dividends is separated from the strike price by a nonvanishing margin on the interval [0,T), where T is the maturity date.      

Mean square error for the Leland–Lott hedging strategy: convex pay-offs

Leland’s approach to the hedging of derivatives under proportional transaction costs is based on an approximate replication of the European-type contingent claim V _T using the classical Black–Scholes formula with a suitably enlarged volatility. The formal mathematical framework is a scheme of series, i.e., a sequence of models with transaction cost coefficients k _n =k ₀ n ^−α , where α∈[0,1/2] and n is the number of portfolio revision dates. The enlarged volatility [^(s)]_n\widehat{\sigma}_{n} in general depends on n except for the case which was investigated in detail by Lott, to whom belongs the first rigorous result on convergence of the approximating portfolio value Vⁿ_TV^{n}_{T} to the pay-off V _T . In this paper, we consider only the Lott case α=1/2. We prove first, for an arbitrary pay-off V _T =G(S _T ) where G is a convex piecewise smooth function, that the mean square approximation error converges to zero with rate n ^−1/2 in L ² and find the first order term of the asymptotics. We are working in a setting with non-uniform revision intervals and establish the asymptotic expansion when the revision dates are t_iⁿ=g(i/n)t_{i}^{n}=g(i/n), where the strictly increasing scale function g:[0,1]→[0,1] and its inverse f are continuous with their first and second derivatives on the whole interval, or g(t)=1−(1−t) ^β , β≥1. We show that the sequence n^1/2(V_Tⁿ-V_T)n^{1/2}(V_{T}^{n}-V_{T}) converges in law to a random variable which is the terminal value of a component of a two-dimensional Markov diffusion process and calculate the limit. Our central result is a functional limit theorem for the discrepancy process.     

A new closed-form solution as an extension of the Black–Scholes formula allowing smile curve plotting

In this paper, as a generalization of the Black–Scholes (BS) model, we elaborate a new closed-form solution for a uni-dimensional European option pricing model called the J-model. This closed-form solution is based on a new stochastic process, called the J-process, which is an extension of the Wiener process satisfying the martingale property. The J-process is based on a new statistical law called the J-law, which is an extension of the normal law. The J-law relies on four parameters in its general form. It has interesting asymmetry and tail properties, allowing it to fit the reality of financial markets with good accuracy, which is not the case for the normal law. Despite the use of one state variable, we find results similar to those of Heston dealing with the bi-dimensional stochastic volatility problem for pricing European calls. Inverting the BS formula, we plot the smile curve related to this closed-form solution. The J-model can also serve to determine the implied volatility by inverting the J-formula and can be used to price other kinds of options such as American options.     

AN ANALYSIS OF THE WALL STREET JOURNAL'S COVERAGE OF CORPORATE NEWS AND THE RESEARCH DESIGN OF EVENT STUDIES

The typical event study of corporate news restricts its sample of announcements to events reported in the Wall Street Journal (WSJ) and listed in the WSJ Index. In this paper we examine whether such samples are representative of the events omitted from the WSJ. Focusing on convertible calls in the 1980s, we analyze possible differences between a sample based only on the WSJ Index and a larger but similarly constructed sample of calls reported in the Dow Jones News Service but not in the WSJ Index. Numerous parametric and nonparametric tests reveal no significant cross-sample divergences in key attributes of the calling firms and called bonds, or in the distributions of risk-adjusted returns around announcements. This evidence suggests that WSJ-based samples for other corporate news items can be representative of cases not covered by the WSJ. Further, the evidence indicates that the results of event studies using WSJ-based samples may support inferences about events not reported in the newspaper.     

Real option pricing with mean-reverting investment and project value

In this work, we are concerned with valuing the option to invest in a project when the project value and the investment cost are both mean-reverting. Previous works on stochastic project and investment cost concentrate on geometric Brownian motions (GBMs) for driving the factors. However, when the project involved is linked to commodities, mean-reverting assumptions are more meaningful. Here, we introduce a model and prove that the optimal exercise strategy is not a function of the ratio of the project value to the investment V/I – contrary to the GBM case. We also demonstrate that the limiting trigger curve as maturity approaches traces out a nonlinear curve in (V, I) space and derive its explicit form. Finally, we numerically investigate the finite-horizon problem, using the Fourier space time-stepping algorithm of Jaimungal and Surkov [2009. Lev´y based cross-commodity models and derivative valuation. SIAM Journal of Financial Mathematics, to appear. http://www.ssrn.com/abstract=972837]. Numerically, the optimal exercise policies are found to be approximately linear in V/I; however, contrary to the GBM case they are not described by a curve of the form V*/I*=c(t). The option price behavior as well as the trigger curve behavior nicely generalize earlier one-factor model results.